What are tent coatings and deniers?
I’m looking for a new family tent and confused about fabric ratings. One store’s website says something about 1,000mm coatings, but I don't see any references to that on other sites. I did see one that said "70 denier." What's that and how do I compare? Robin Highland, Indiana
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Coatings and deniers are different things, but equally confusing. Well start with coatings. All tents have polyurethane coating on the floor and waterproof fly, and its the coating that keeps you dry, not the fabric itself. A coating of, say, 1,000mm doesnt mean the coating is that thickthat would make it nearly 40 inches thick. Instead, its a measure of how much hydrostatic pressure the coating can take before it leaks. That test is accomplished by securing a selected piece of fabric to the end of a long tube, to which water is added. The 1,000mm designation means that 1,000mm of water can be added before the coating leaks.
REI Hobitat 4Hobitat 4
Obviously, a higher number is better, as a thin coating is less resistant to abrasion and therefore more apt to fail. For a tent floor, Id say about 1,000mm pressure resistance is the minimum for wet conditions. The fly can get away with a lower rating because youre not kneeling on it and potentially squeezing water through the fabric. High-end backpacking tents will have floor coatings rated to as much as 3,500mm.
Denier (pronounced den-YAY) is a unit of measurement that applies to a yarns thickness. Packs often have fabric with a denier of 500 or morepretty heavy stuff, for more durability (but also with big gaps between fibers, which is why its so difficult to waterproof a pack). Clothing uses much finer yarn, so the denier there is often around 70 or so. In tents youll find a mix, depending on where the fabric is used, with a denier of 75 and 150 most commonly found.
You dont say what kind of tent youre looking for. If car camping, then a good choice for a family of four is REIs new Hobitat 4 ($259; www.rei.com) or Hobitat 6 ($329). These are exceptionally sturdy tents for their size, with a rugged 300-denier floor and a coating rated to 1,500mm. I also like the Eureka! Equinox ($349; www.eurekatent.com), which sleeps six. Its floor is rated to 1,200mm.
I almost always recommend that tent users place something under the tent to protect the floor from abrasion. Most tent manufacturers will happily sell you a footprint” for $40 or more. But you can buy some light polyethylene sheeting at your local hardware store and cut yourself a piece. Make it slightly smaller than the size of the floor, so water dripping off the tent doesnt catch on the footprint and collect under the tent.
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